#include"Stack.h"

void STInit(ST* ps)
{
	assert(ps);

	ps->a = NULL;
	ps->top = 0;
	ps->capacity = 0;
}
void STDestroy(ST* ps)
{
	assert(ps);

	free(ps->a);
	ps->a = NULL;
	ps->top = ps->capacity = 0;
}

void STPush(ST* ps, STDataType x)
{
	assert(ps);

	if (ps->top == ps->capacity)
	{
		(ps->capacity) == 0 ? (ps->capacity=4) : (ps->capacity *= 2);
		STDataType* tmp = (STDataType*)realloc(ps->a, sizeof(STDataType) * (ps->capacity));
		if (tmp == NULL)
		{
			perror("realloc failed");
			exit(-1);
		}

		ps->a = tmp;
	}
	ps->a[ps->top++] = x;
}
void STPop(ST* ps)
{
	assert(ps);
	assert(ps->top > 0);
	ps->top--;
}
STDataType STTop(ST* ps)
{
	assert(ps);
	return ps->a[ps->top - 1];
}

bool STEmpty(ST* ps)
{
	assert(ps);
	return ps->top == 0;
}
int STSize(ST* ps)
{
	assert(ps);
	return ps->top;
}
